This invention relates to valves and, in particular, to ball valves. The use of ball valves to start and stop the flow of fluids is well known in the art. Ball valves have an interior body cavity defined in a valve body between two concentric, annular sealing seats.
The sealing seats in conventional ball valves are fabricated from any one of a number of different materials, such as, for example, a metal, a ceramic, a carbide, a carbide-coated metal, or an elastomer, and are then inserted into the valve. The inventor of the present invention designed a ball valve having at least one of the sealing seats as an integral portion of the ball valve body.
Should a ball valve begin to leak, the amount of fluid that leaks past a valve seat may initially be insufficient to be detected, or to have any visible external effects. Nevertheless, once a valve seat begins to leak, the area of the seat over which the leakage occurs typically erodes further. The leakage rate may increase, and the fluid that leaks through the ball valve may damage downstream equipment or processes, or cause other detrimental and undesirable effects. The ball valves of the prior art provide an inadequate means of determining the condition or effectiveness of the seats at a sufficiently early stage of leakage to permit convenient and effective corrective action.
Therefore, a ball valve is needed in which leakage across a seat is minimized, and is readily detectable before downstream equipment or processes are damaged, or before other detrimental or undesirable effects occur.